In some embodiments, an electronic device with a display and a touch-sensitive surface displays a user interface object. Each power train includes a power factor correction circuit that receives an AC input and generates a first DC output, and a DCDC converter circuit that receives the first DC output and generates a second regulated DC output. The inductance of a series connected loading coil is continuously varied to resonate the antenna capacitance. Play-indicating mechanisms are attached to the table. The scraper system may be used in a first mode in which the first scraper edge is used to remove caulk beads from the at least one surface and a second mode in which the second scraper edge is used to remove caulk beads from a plurality of surfaces.